Alnylam's RNAi therapy Givlaari shows lasting effect one year into treatment, new data show

Alnylam received FDA approval for Givlaari in November. (Alnylam)

When Alnylam scored an FDA approval for its second RNAi therapy, Givlaari, late last year, some market watchers cast a wary eye on the drug's short stay in the clinic and questionable safety profile. But after eight months on the market, Alnylam is touting longer-term, open-label data for Givlaari that could put some of those worries to rest.

Givlaari showed a sustained effect in reducing the number of "attacks," some of which require hospitalizations, in patients with ultra-rare liver disease acute hepatic porphyria at the one-year mark, according to data from an open-label extension of the phase 3 Envision study presented during a Tuesday webinar.

The 12-month data reinforce six-month, double-blind Envision results published in The New England Journal of Medicine earlier this month showing Givlaari beat out placebo in reducing patients' attacks. In the open-label period, Givlaari showed safety results comparable to those it posted in the earlier trial, potentially putting away some concern over the drug's iffy safety profile for long-term use.

According to Eliane Sardh, M.D., Ph.D., the study's lead investigator and head of the Swedish Porphyria Centre, the longer-term data should show specialists in the disease that monthly infusions of Givlaari continue to benefit patients without any added side-effect burden.

"This is really something that we are looking forward to have in clinical practice," Sardh said. "I would say that this is a breakthrough for us … that it is possible to give them a treatment that may help."

RELATED: Alnylam wins FDA nod for $575,000 liver med Givlaari despite safety flags

In November, the FDA approved Givlaari as the first RNAi therapy for acute hepatic porphyria, an ultra-rare liver disease caused by the low production of an enzyme central to hemoglobin function.

The treatment, which came with a $575,000-per-year list price before discounts, sports an FDA-approved label that includes the risk of liver and kidney toxicity as well as allergic and injection site reactions.

The drug's 12-month data not only showed no major safety differences—for better or worse—but it also showed a greater patient benefit when Givlaari is given at a higher dose, Sardh said. Patients treated in the open-label study are currently being transitioned to the higher dose of Givlaari "due to evidence for increased efficacy," Alnylam said in a release.

In the first quarter, Givlaari raked in just $5.3 million for Alnylam, which just topped the Street's consensus of $4 million.

RELATED: JPM: Alnylam CEO looks to action-packed 2020 on the heels of Givlaari approval

Givlaari is Alnylam's second RNA interference med to market, joining Onpattro, which has an FDA approval to treat peripheral nerve disease caused by hereditary transthyretin-mediated amyloidosis.

Despite Onpattro facing a stiff challenge from Pfizer's Vyndaqel in that same indiction, Alnylam is predicting big things in the coming years on the backs of its two RNAi therapies and a potentially lucrative pipeline.

Alnylam has four late-stage candidates—including two partnered drugs—approaching FDA approval decisions in the next six to 18 months, which could significantly expand the drugmaker's portfolio beyond Givlaari and Onpattro.

If Alnylam does make the jump from two marketed meds to six in the coming years, it could be on its way to a "top five" position in biopharma based on the strength of its launches and budding portfolio, CEO John Maraganore said in January at the annual J.P. Morgan Healthcare Conference.